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A paradigm shift to combat indoor respiratory infection

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Re: A paradigm shift to combat indoor respiratory infection

#71

Post by sandworm101 »

ddxxdd wrote: post #29
zargon wrote: post #9

Earlier quoted context omitted.

The WHO and CDC have had their head in the sand for 60 years when it comes to airborne pathogens. They have only acknowledged aerosol transmission of covid in the last couple weeks. It was physicists who had to figure out why they were domatically denying reality. https://www.wired.com/story/the-teeny-tiny-scientific-screwu...

Apparently the CDC has yet to catch up to 19th century physics. The physics of small particles moving in the air ("Brownian motion") was completely figured out by Einstein back in 1905. Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne.

>> Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne.

How long it remains airborne is beside the point. Does that physics grad know how long/if the virus can survive once it dries up? Do they know how long it will survive exposure to light? Do then know whether the virus can cling to dust particles?

Even brownian motion is only half the story. Does the physics grad understand airflow in office spaces? Do they understand how fast air moves when a person coughs? How much turbulence is caused by opening an office door? Plenty of things can stay airborne for extended periods because of aerodynamics without regard to brownian motion (snow/rain/dust/salt etc). That physics grad better come with minors in aerodynamics, kinesiology, microbiology ... even some basic meteorology would be helpful.

Re: A paradigm shift to combat indoor respiratory infection

#72

Post by op00to »

colechristensen wrote: post #8

It seems overly complicated. Just raise the air exchange per person and or per volume by a significant factor and mandate a very fine particulate filter. You could do many measurements and lots of theory but nobody is going to engineer their buildings like cleanrooms anyway so the results of a lot of science wouldn’t be so good regardless.

If you have air exchange per person, but some people are in an airflow "dead zone", then that doesn't really do you any good. You need to ensure the personal area is actively ventilated, versus the entire space as a whole.

Re: A paradigm shift to combat indoor respiratory infection

#74

Post by Enginerrrd »

sandworm101 wrote: post #71
ddxxdd wrote: post #29

Earlier quoted context omitted.

Apparently the CDC has yet to catch up to 19th century physics. The physics of small particles moving in the air ("Brownian motion") was completely figured out by Einstein back in 1905. Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne.

>> Given a virus' size and weight, it should be trivial for a physics graduate student to simulate how long it will be airborne. How long it remains airborne is beside the point. Does that physics grad know how long/if the virus can survive once it dries up? Do they know how long it will survive exposure to light? Do then know whether the virus can cling to dust particles? Even brownian motion is only half the story.…

As an civil / environmental engineer, I can assure you that particle size and average settling time is INCREDIBLY important to consider and will cover basically all of your supposed edge cases to the point of being statistically irrelevant. You would handle those edge cases by simply including a safety factor in the required residence time of the average particle within the system considered (or equivalently, you'd specify a certain log removal of pathogens). The end result of all your edge cases that you seem to think are so important is something like: "Ok, 1 in 100,000 may still get sick with this design. Good enough."

You can make the same arguments for drinking water, and yet, as long as you follow the rules, it is unbelievably safe, despite the fact that no one gave a shit about turbulence along the baffles in the treatment tank.

Re: A paradigm shift to combat indoor respiratory infection

#75

Post by Enginerrrd »

richardw wrote: post #65
londons_explore wrote: post #58

Earlier quoted context omitted.

Wikipedia claims "Heat recovery systems typically recover about 60–95% of the heat in exhaust air". But even recovering 95% of heat isn't exactly great. If you live in Canada and have a 2600 sq ft house with 8 ft ceilings and 10 changes of air per hour, and the indoors is 70F and outdoors is 0F, thats 2600 8 10 cubic feet of air/ per hour, or 12000 BTU/hr. That means you are more than doubling your heating costs comp…

It can’t be that hard to focus on the rooms with people in them, reduce the other rooms to eg one change an hour.

This is already done when calculating ventilation rates. It won't matter much because the majority of space in an occupied building is going to be classified as, well, occupied.

Re: A paradigm shift to combat indoor respiratory infection

#76

Post by Enginerrrd »

ur-whale wrote: post #48
f6v wrote: post #43

Earlier quoted context omitted.

You still eat fresh fruits and vegetables, touch the surfaces on your way to work etc. There’re countless pathogens everywhere. So I guess we would be fine? You’re right that our immune system didn’t evolve to be in a sterile environment. But we also weren’t meant to be that close to that many humans.

>So I guess we would be fine? Can you catch airborne respiratory diseases from eating fruit? What I'm saying is: we run the risk of never being able to go outside again if we eliminate all airborne pathogens.

Not to worry, people will still have children, and I assure you, they'll still go out into the world and lick the doorknobs/each other and get you sick so you can bring it to work.

Re: A paradigm shift to combat indoor respiratory infection

#77

Post by SideburnsOfDoom »

newsbinator wrote: post #19
zargon wrote: post #9

Earlier quoted context omitted.

The WHO and CDC have had their head in the sand for 60 years when it comes to airborne pathogens. They have only acknowledged aerosol transmission of covid in the last couple weeks. It was physicists who had to figure out why they were domatically denying reality. https://www.wired.com/story/the-teeny-tiny-scientific-screwu...

> EARLY ONE MORNING, Linsey Marr tiptoed to her dining room table, slipped on a headset, and fired up Zoom. On her computer screen, dozens of familiar faces began to appear. She also saw a few people she didn’t know It’s really hard for me to read a WIRED article for information. I mean I realize that’s not what it’s there for but it takes forever to get into the content of the article.

I have read both now, and IMHO there's more actual content about scientific matters in the Wired piece.

Re: A paradigm shift to combat indoor respiratory infection

#78

Post by TeMPOraL »

pbronez wrote: post #68
dorfsmay wrote: post #54

Earlier quoted context omitted.

I know this is going to sound crazy, but give it a try sometime. When I lose track while reading an article, or find difficult to understand it, I stop and reading it bottom up, one paragraph at a time. First the last paragraph, then the one before that, etc... This cuts through directly to the conclusion, then the detailed explanations form particular to general (which works better for me) and I can skip the "excite…

man... this is exactly the opposite of how news articles are supposed to be written. Good news articles should tell you everything in the headline. Then tell you everything again in the first body sentence. Then tell you everything again in the first paragraph. and the first page. And so on. It's supposed to be a fractal that unfolds additional detail as you press forward, while ensuring that even a casual reader com…

Yeah, it's called "inverted pyramid", and it's supposed to be the gold standard of journalistic writing. IIRC it's being taught as part of vocational education.

And yet, news media are the last place you're likely to find articles written in this style. Somehow, they manage to deliver the exact opposite of what they should be. A fractal of confusion, recursively unfolding noise.

(It's as if they were making a lot of money on maximizing the time a reader is engaged with any given article. It's as if - and I know this sounds crazy - the articles were there just to hold the user down, while they're being exposed to something else...)

Re: A paradigm shift to combat indoor respiratory infection

#79

Post by jerf »

pbronez wrote: post #68
dorfsmay wrote: post #54

Earlier quoted context omitted.

I know this is going to sound crazy, but give it a try sometime. When I lose track while reading an article, or find difficult to understand it, I stop and reading it bottom up, one paragraph at a time. First the last paragraph, then the one before that, etc... This cuts through directly to the conclusion, then the detailed explanations form particular to general (which works better for me) and I can skip the "excite…

man... this is exactly the opposite of how news articles are supposed to be written. Good news articles should tell you everything in the headline. Then tell you everything again in the first body sentence. Then tell you everything again in the first paragraph. and the first page. And so on. It's supposed to be a fractal that unfolds additional detail as you press forward, while ensuring that even a casual reader com…

"this is exactly the opposite of how news articles are supposed to be written."

I'm not accusing you of doing this on purpose, but there's a certain amount of equivocation in the phrase "news article" there. Yes, that's a style that is recommended for factual news articles in a newspaper context, but that's not the only form of "news article".

Call this a "news essay" instead and give it its own style and it might make more sense. It's been around for a long time. Could call it the 20th-century equivalent of clickbait and probably not be far off.

"There's an exciting revolutionary change to physics coming... but first, the full life story of the thesis advisor's influential father... keep reading...."

Arguably it's more a form of entertainment than information.

Re: A paradigm shift to combat indoor respiratory infection

#80

Post by Joker_vD »

daniellarusso wrote: post #41
prof-dr-ir wrote: post #7

From the article: "It is not known exactly what fraction of infections could be prevented if all building and transport ventilation systems on the planet were ideal (in terms of controlling airborne infections), or the cost of design and retrofitting to make them ideal." I think this is the key question. Surely better ventilation would have prevented some infections in the covid pandemic. But how many? And to decide…

This is the Ben Franklin / John Adams debate when they shared a small room together overnight with one window. “When Adams explained that he didn’t want to catch an illness from the cold night air, Franklin countered that the air in their room was even worse.” https://www.mentalfloss.com/article/54169/time-ben-franklin-...

Miasma theory rears its ugly head once again: https://en.wikipedia.org/wiki/Miasma_theory#Contagionism_ver...

The night air is dangerous, close those windows before you go to sleep!

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